Single most important thing regarding break-in is to not to try and shoot too far too quickly. You need to go gradually in steps. Maybe 20 shots at 50 yards, clean it, 20 shots at 75 yards, clean it, 20 shots at 100, clean, 20 shots at 125 yards, cleain it again, 20 shots at 150, etc., etc., etc..

Nice and easy or you'll wind up with what's known as a "short shooter", these are the ones lining the used rifle racks at the shops.

Uncle Matt (in IL)